Swabbing as a Non-Lethal DNA Collection Method for Earthworm Barcoding: Performance and Citizen Science Perspectives

Area of Science:

• Molecular Biology
• Ecology
• Biodiversity Research

Background:

• Traditional earthworm DNA barcoding relies on lethal tissue sampling, posing ecological concerns and potential public disengagement.
• Citizen Science (CS) projects face challenges with methods that elicit negative emotional responses.
• Non-lethal sampling methods are needed to improve ecological compatibility and public acceptance in biodiversity research.

Purpose of the Study:

• To evaluate the performance of swab sampling as a non-lethal alternative for earthworm DNA barcoding.
• To compare DNA yield and quality from swab sampling versus traditional tissue sampling methods.
• To assess the suitability of swab sampling for CS-based biodiversity and barcoding initiatives.

Main Methods:

• Compared three DNA collection methods: Swab-QIAGEN, Tissue-QIAGEN, and Tissue-Chelex.
• Generated cytochrome c oxidase I (COI) barcodes from 40 adult earthworms.
• Assessed PCR amplification success, sequencing success rates, and barcode quality metrics.

Main Results:

• All methods exhibited high PCR amplification success rates (97.5%-100%).
• Swab-QIAGEN yielded a lower sequencing success rate (66.7%) but produced the highest proportion of reference-quality barcodes (80.8%) among functional sequences.
• All methods demonstrated high concordance between morphospecies identification and genetic data (>90%), with consistent taxonomic assignments and low sequencing error rates (<0.1%).

Conclusions:

• Swab sampling is a viable, non-lethal method for earthworm DNA barcoding, showing high interoperability with tissue sampling.
• The method shows potential for CS projects by being emotionally adaptive and ecologically advantageous.
• Standardization of the swabbing methodology is necessary for its reliable implementation in CS-based earthworm barcoding.